Where’s my speed at?
#11
Registered
I haven’t checked my gear ratio, I assume it’s 1.5 and it’s one step. The prop is the original 3-blade stainless steel quicksilver prop which seems to be flawless. I think everything is original on this boat, if it’s the 1.5 gear ratio, that’s means I’m getting like a 33% slip. I don’t know if the RPMs are right but that’s what I’m seeing. I can’t do anything right now as it’s winter here.
#12
Registered
I haven’t checked my gear ratio, I assume it’s 1.5 and it’s one step. The prop is the original 3-blade stainless steel quicksilver prop which seems to be flawless. I think everything is original on this boat, if it’s the 1.5 gear ratio, that’s means I’m getting like a 33% slip. I don’t know if the RPMs are right but that’s what I’m seeing. I can’t do anything right now as it’s winter here.
#13
*
Platinum Member
First off , I'm a little skeptical that the step on your hull adds +10mph over a straight V of the same size , weight and power .
Secondly , maybe someone can clarify , but I thought that all OBs and stern drives have been prop shaft HP rated since sometime in the 1980s .
IMO 53 MPH out of a single 350hp engine in a boat of that configuration doesn't sound too far off normal . Maybe even more so if the bottom is painted .
As has already been mentioned , I'd first confirm that your tach is calibrated correctly .
Secondly , maybe someone can clarify , but I thought that all OBs and stern drives have been prop shaft HP rated since sometime in the 1980s .
IMO 53 MPH out of a single 350hp engine in a boat of that configuration doesn't sound too far off normal . Maybe even more so if the bottom is painted .
As has already been mentioned , I'd first confirm that your tach is calibrated correctly .
#14
I never noticed any vibration or anything like that from the prop. It’s not waterlogged or anything like that either. The hull does add 10mph over conventional, it’s fairly light for its size at 4,000lbs dry weight, while my dad’s 1994 225CCR weighs 3,900lbs (350 mag, alpha 1 and stainless steel prop) and tops out at 47mph. I’ll test the tach firstly in the summer since I live in Ny. I’ll look into different props as well. I found an old listing for my boat, the guy stated that it did 66mph top speed back in 2011 and I’m fairly certain that nothing was changed since then. I’ll have to check the gear ratio to make sure it’s 1.5, my guess is that’s what it is. This boat has all the extras besides captains choice exhaust, just has thru-hull. Just based on what other owners stated and the test boats, this should be running much faster. I also remembered that at slow no wake speeds, I get a lot of wandering, maybe a 4 blade would help this as well?
Last edited by Prestigeworldwideee; 02-17-2019 at 05:49 PM.
#15
Sounds like a prop or a tach problem. 350 hp and a boat with fuel and passengers added to a dry weight of 4000 lbs would likely run in the mid 50’s. With a good bottom and lots of prop testing, you might break into the low 60’s. Good luck with your boat.
#17
Registered
My drive was labeled 1.50 but when I pulled it off someone had changed the gears and scribed 1.65 on it. A lot of fountains came with 1.65 drives that may have found its way to your boat.
#18
The boat doesn’t seem to have had that much use out of it, I would be very surprised to hear that it wasn’t all original. It’s a bit in accessible at the moment so checking the gear ratio will have to wait, checking the tachometer will have to wait till the summer and any other diagnostics as well. I’ve seen the same setup as I have in another spectre and it ran like 68 MPH on GPS. I’ll be back here when I figure out the gear ratio.
#19
Banned
I doubt the tach is correct -- pole setting off on the back of the tach.
can a stock carb 454 mag even get up to 5500 / 5600 without floating the valves ?
If I recall a 1990 454 mag carb is 330 hp I would have to look that up. A 23 correct pitch prop is not going to spin that engine up to 5500 rpms.
can a stock carb 454 mag even get up to 5500 / 5600 without floating the valves ?
If I recall a 1990 454 mag carb is 330 hp I would have to look that up. A 23 correct pitch prop is not going to spin that engine up to 5500 rpms.